A stent is an expandable, tubular, mesh-like device composed of stainless steel which is commonly used in conjunction with the performance of a balloon angioplasty (PTCA).

Initially in the 1970's with the invention and introduction of balloon angioplasty, 30-50% of the time, a balloon angioplasty result would tend to reoccur (re-stenose) somewhere between 4-6 months later. This was a very frustrating situation for cardiologists and patients alike. It was then discovered that the implantation of a support (stent) device inside an artery that had been angioplastied decreased the liklihood of spontaneous re-narrowing of the artery. The re-stenosis rate of the artery went from somewhere around 30-50% down to around 15-20% with the introduction of the stent into the artery. A stent, when feasible*, was the preferred treatment done in association with balloon angioplasty

*A variety of factors are investigated when determining whether or not stents are an appropriate treatment. Artery size is one of the key factors. If an artery is very small, a stent is often not recommended.